Abstract: The exponential functions of deterioration depth, complete deterioration depth and deterioration transition layer depth over time were established via indoor deterioration test on cement soil. The experimental results showed that the initial strength of cement-soil had no significant influence on the penetration resistance curve of degraded cement-soil. As an inhomogeneous body with the deterioration degree increasing with time, degraded cement-soil was composed of three parts: the completely degraded layer with a strength of almost zero, the transition layer whose strength increased with depth, and the undegraded zone whose strength could be regarded as the same as the standard curing cement-soil of the same age period. The deterioration depth, complete deterioration depth and transition layer depth of cement-soil reduced with the augment of the initial strength of cement-soil. In the prediction formula of deterioration depth against time, the coefficients were respectively the deterioration depth of cement-soil at 90 days of deterioration, the complete deterioration depth, and the deterioration transition layer depth. The value of the index was 0.6 regardless of the degradation type, indoor degradation test or field degradation test. At this time, the calculation results were consistent with the test results, and the formula could be used to predict the deterioration depth of cement-soil.

Key words: cement soil, corrosion field, micro-penetration test, degradation depth, prediction